Nuclear-cytoplasmic asynchrony appears to characterize the bone marrow plasma cells of patients with multiple myeloma. This study will explore the relationship between the seemingly specific morphologic abnormality and the proliferative potential of the abnormal cells in tissue culture. The degree of morphologic asynchrony will be correlated with cell mass, as estimated by sequential experimental measurement, to determine if asynchrony reflects either myeloma cell mass or rate of expansion of the myeloma cell mass. Tritiated thymidine incorporation and radioautography will be combined with electron microscopic, light microscopic, and fluorescent antibody analysis of the bone marrow cells. The therapeutic and prognostic implications of the abnormality will be assessed by longitudinal patient studies, with special reference to the predictive value this abnormality may have for response to treatment. The relationship, if any, of peripheral lymphocyte populations and subpopulations to the myelomacell mass will be assessed, using both morpholigic and biosynthetic markers of the malignant clone.